Many varieties of footwear have been worn by people of all cultures for thousands of years. People use footwear that range in type from athletic shoes, to boots, to sandals, to other specialized types of footwear such as baseball cleats or ballet shoes. People use footwear to protect their feet from the surfaces on which they walk, to reduce the shock to their feet and ankles from physical activity, and to provide support and comfort. People depend on their footwear to support their feet and ankles, even when walking outdoors on rough or uneven surfaces. People use footwear for a large portion of their lives and so want their footwear to be comfortable, well-cushioned, and to support their feet during all of their activities. The bottom of a person's foot comes into contact with, and is supported by, the sole structure of their footwear and so the sole is the part of an article of footwear that must be particularly well-cushioned and supportive.
Prior articles of footwear have had soles which separate a wearer's foot from the surface on which that wearer is present. Many materials and techniques have been used to provide improved cushioning and support for a wearer's foot. Some articles of footwear have magnets in their soles to help support the weight of their wearer, but do so in the context of other cushioning or support systems. Prior footwear has not used magnetic forces as the primary means of support, or to levitate a wearer's foot, in order to avoid shocks and stresses transmitted through contact of a wearer's footwear with the ground.
Some prior art footwear has hollowed heel cavities with a number of springs extending from the top of the cavity to the bottom of the cavity to cushion and support a wearer's heel, with opposing magnets mounted in the cavity to aid the springs in cushioning a wearer's foot. Other prior art footwear use multiple mechanical shock absorbers placed inside of and around the sole with a flexible middle sole having a cavity filled with water or gel and an innersole having multiple cavities filled with compressed air and nitrogen bubbles kept separated by repulsive forces generated by magnets. Yet other prior art footwear has sole structures with two magnets placed inside of a heel cavity, with a foam rubber spacer separating the magnets and filling the remainder of the cavity, such that magnetic forces cushion a user's heel in conjunction with foam rubber and a large heel structure. Such prior art footwear use a substantially solid sole as the primary support for a wearer's foot.